Chemical analysis and biomedical diagnostics commonly use absorption, fluorescence, chemiluminescence, UV-Vis and Raman scattering to detect the presence of an analyte. For example, enzyme-linked immunosorbent assays (ELISA) are widely used to detect an analyte. ELISA assays are typically performed in microwell plates, and require multiple steps of adding reagents, washing the reactant plates, and applying a reaction substrate that is converted to provide a chromogenic (colorimetric) or fluorescent signal. Furthermore, its detection limit ranges from the micromolar to picomolar or nanograms to pictograms of protein analyte per milliliter of a sample. For markers with low copy numbers, more sensitive detection technology is needed.
The current methods and devices for detecting the presence of an analyte in a sample have multiple drawbacks. First, the sizes of the devices are too big to be used in field applications or at home environment, such as point-of-care (POC) environment. Second, the current devices require a large amount of sample, which not only is infeasible for certain applications, but also hinders activities such as mixing and heating of the sample required for many analyses. Third, the current devices have complex structures for fluidic control and are often not self-contained. Fourth, current devices are limited by their detection sensitivity. Fifth, the current devices are often designed for specialized applications, e.g. protein analysis only, or nucleic acid only. Thus, there is a need for miniaturized, integrated, and versatile devices for analysis of a sample suspected of containing an analyte that can perform on-site, flexible, rapid, sensitive, and/or efficient analysis.